Abstract:

A piezoelectric oscillator part capable of suppressing oscillation that
leaks from a piezoelectric oscillator to a substrate side is obtained.
The piezoelectric oscillator part has a piezoelectric oscillator held on
a substrate by first and second conductive holding members. The first
conductive holding member is arranged proximal to a first end of the
substrate. A terminal electrode connected to the first conductive holding
member is arranged proximal to a second end of the substrate opposite the
first end. The first conductive holding member and the terminal electrode
are electrically connected by a wiring electrode.

Claims:

1. A piezoelectric oscillator part, comprising:a substrate having an upper
surface and a lower surface;a piezoelectric oscillator;a conductive
holding member connecting the substrate and the piezoelectric oscillator
in such a manner as to hold the piezoelectric oscillator above the upper
surface of the substrate, the conductive holding member being proximal to
a first end of the substrate and electrically connected to the
piezoelectric oscillator;a terminal electrode proximal to a second end of
the substrate opposite the first end; anda wiring electrode on the upper
surface of the substrate and connecting the conductive holding member and
the terminal electrode.

2. The piezoelectric oscillator part according to claim 1, wherein the
piezoelectric oscillator is held by the conductive holding member on the
upper surface of the substrate in a cantilever manner.

3. The piezoelectric oscillator part according to claim 2, wherein the
substrate has a shape of a rectangular plane having a first short side
and a second short side facing each other, and a third long side and a
fourth long side facing each other, andwherein the conductive holding
member is arranged proximal to the first short side, and the terminal
electrode is arranged proximal to the second short side.

4. The piezoelectric oscillator part according to claim 1,wherein the
conductive holding member is a first conductive holding member, the
terminal electrode is a first terminal electrode, and the wiring
electrode is a first wiring electrode, the piezoelectric oscillator part
further comprising:a second conductive holding member proximal to the
second side of the substrate;a second terminal electrode proximal to the
first side of the substrate;a second wiring electrode on the upper
surface of the substrate and connecting the second conductive holding
member and the second terminal electrode.

5. The piezoelectric oscillator part according to claim 4, wherein the
first wiring electrode has a length sufficient to attenuate oscillation
leakage from the first conductive holding member, and the second wiring
electrode has a length sufficient to attenuate oscillation leakage from
the second conductive holding member.

6. The piezoelectric oscillator part according to claim 1, further
comprising a resin layer on the upper surface of the substrate and
covering at least part of the wiring electrode.

7. The piezoelectric oscillator part according to claim 1, further
comprising a cap, having an opening on a substrate side thereof, fixed to
the substrate so as to surround the piezoelectric oscillator.

8. The piezoelectric oscillator part according to claim 7, further
comprising a resin layer on the upper surface of the substrate covering
at least part of the wiring electrode.

9. The piezoelectric oscillator part according to claim 8, wherein an
adhesive fixes the cap to the substrate, the adhesive forming the resin
layer.

10. The piezoelectric oscillator part according to claim 1, wherein the
terminal electrode is provided in a concavity at a corner of the
substrate.

11. The piezoelectric oscillator part according to claim 1, wherein the
wiring electrode has a length sufficient to attenuate leakage oscillation
from the conductive holding member.

12. The piezoelectric oscillator part according to claim 1,wherein the
conductive holding member is a first conductive holding member, the
terminal electrode is a first terminal electrode, and the wiring
electrode is a first wiring electrode, the piezoelectric oscillator part
further comprising:a second conductive holding member proximal to the
first side of the substrate;a second terminal electrode proximal to the
second side of the substrate;a second wiring electrode on the upper
surface of the substrate and connecting the second conductive holding
member and the second terminal electrode.

13. The piezoelectric oscillator part according to claim 12, wherein the
first wiring electrode has a length sufficient to attenuate oscillation
leakage from the first conductive holding member, and the second wiring
electrode has a length sufficient to attenuate oscillation leakage from
the second conductive holding member.

Description:

CROSS REFERENCE TO RELATED APPLICATIONS

[0001]The present application is a continuation of International
Application No. PCT/JP2009/001438, filed Mar. 30, 2009, which claims
priority to Japanese Patent Application No. JP2008-091467, filed Mar. 31,
2008, the entire contents of each of these applications being
incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

[0002]The present invention relates to a piezoelectric oscillator part
used in, for example, a piezoelectric resonator part or piezoelectric
actuator, and more specifically to a piezoelectric oscillator part with a
structure in which a piezoelectric oscillator is mounted on a substrate
so as to be able to oscillate by the piezoelectric effect.

BACKGROUND OF THE INVENTION

[0003]Hitherto, various piezoelectric oscillator parts have been proposed
as oscillators or filters. A piezoelectric oscillator part, in which a
piezoelectric oscillator oscillates, requires a packaging structure which
does not hinder the oscillation of the piezoelectric oscillator. The
piezoelectric oscillator part disclosed in Patent document 1 employs a
packaging structure constituted by a case substrate and a cap.

[0004]FIGS. 8(a) and 8(b) are exploded perspective views of a conventional
piezoelectric oscillator part having such a packaging structure. A
piezoelectric oscillator part 101 includes a piezoelectric oscillator 103
mounted on a case substrate 102. Here, first and second terminal
electrodes 104 and 105 for external electrical connection are formed in
the first and second corner portions 102a and 102b of the case substrate
102. Conductive adhesive portions 106 and 107 are arranged on the surface
of the case substrate 102. The conductive adhesive portions 106 and 107
are electrically connected to wiring electrodes 108 and 109. The
piezoelectric oscillator 103 is fixed to the case substrate 102 with the
conductive adhesive portions 106 and 107, and the piezoelectric
oscillator 103 is electrically connected to the first and second terminal
electrodes 104 and 105 via the wiring electrodes 108 and 109. The
piezoelectric oscillator 103 is supported by the conductive adhesive
portions 106 and 107 at one end thereof using a cantilever structure.

[0005]To form a space for preventing the oscillation of the
above-described piezoelectric oscillator 103 from being hindered, a cap
110 having an opening therebelow is connected to the case substrate 102
with a frame-shaped adhesive layer 111 therebetween.

[0006]Hence, the piezoelectric oscillator 103 is sealed in a package
formed by the case substrate 102 and the cap 110.

[0008]Also in the piezoelectric oscillator part 101, similarly to other
electronic parts, reduction in size is strongly required. However, in the
piezoelectric oscillator part 101, a packaging structure having a sealed
space, as described above, needs to be formed in order not to hinder the
oscillation of the piezoelectric oscillator 103. Hence, reduction in the
size of the piezoelectric oscillator part 101 has been limited.

[0009]Hence, to reduce the size of the piezoelectric oscillator part 101
as much as possible, in the case substrate 102, the distance between the
conductive adhesive portion 106 and the first terminal electrodes 104,
and the distance between the conductive adhesive portion 107 and the
second terminal electrode 105 have conventionally been made as small as
possible.

[0010]On the other hand, in the piezoelectric oscillator part 101, the
oscillation of the piezoelectric oscillator 103 is apt to leak to the
case substrate 102 side through the junctions formed by the conductive
adhesive portions 106 and 107. This leakage of oscillation may cause
deterioration in resonance characteristics and the like.

SUMMARY OF THE INVENTION

[0011]An object of the present invention is to solve the above-described
problems of the conventional technologies and to provide a piezoelectric
oscillator part that allows not only reduction in size but also
controlling the leakage of oscillation from the piezoelectric oscillator
to the case side.

[0012]According to the present invention, a piezoelectric oscillator part
is provided that includes: a substrate having an upper surface and a
lower surface; a piezoelectric oscillator held on the upper surface of
the substrate; a conductive holding member combining the substrate and
the piezoelectric oscillator in such a manner as to hold the
piezoelectric oscillator on the upper surface of the substrate at one end
of the substrate, the conductive holding member being electrically
connected to the piezoelectric oscillator; a terminal electrode provided
close to another end of the substrate; and a wiring electrode provided on
the upper surface of the substrate in such a manner as to connect the
conductive holding member and the terminal electrode.

[0013]In the piezoelectric oscillator part according to the present
invention, the above-described piezoelectric oscillator is held on the
upper surface of a substrate, but this holding method is not limited a
specific method. In a specific aspect of the present invention, the
piezoelectric oscillator is supported by the above-described conductive
holding member on the upper surface of the substrate using a cantilever
structure. In this case, the displacement caused by the piezoelectric
oscillator may be made larger. In addition, the supporting structure is
simplified.

[0014]In another specific aspect of the piezoelectric oscillator part
according to the present invention, the substrate has a shape of a
rectangular plane having a first side and a second side facing each
other, and a third side and a fourth side facing each other; and the
conductive holding member is arranged close to the first side, and the
terminal electrode is arranged close to the second side. Since, in the
substrate having the shape of a rectangular plane, the conductive holding
member is formed close to the first side, and the terminal electrode is
formed close to the second side on the opposite side, a long wiring
electrode may be formed on the upper surface of the substrate.

[0015]In still another specific aspect of the piezoelectric oscillator
part according to the present invention, the substrate has a shape of a
rectangular plane having a first side and a second side facing each
other, and a third side and a fourth side facing each other; and the
conductive holding member includes a first conductive holding member
arranged close to the first side and a second conductive holding member
arranged close to the second side. The piezoelectric oscillator is held
on the upper surface of the substrate by the first and second conductive
holding members; and the terminal electrode includes a first terminal
electrode arranged close to the second side and a second terminal
electrode arranged close to the first side. The wiring electrode includes
a first wiring electrode and a second wiring electrode, and the first
conductive holding member and the first terminal electrode are
electrically connected by the first wiring electrode, and the second
conductive holding member and the second terminal electrode are
electrically connected by the second wiring electrode. In this case, the
lengths of the first and second wiring electrodes may be made
sufficiently long in the structure in which the piezoelectric oscillator
is held by the first conductive holding member arranged close to the
first side of the substrate and the second conductive holding member
arranged close to the second side.

[0016]In still another specific aspect of the piezoelectric oscillator
part according to the present invention, the piezoelectric oscillator
part further includes a resin layer formed on the upper surface of the
substrate in such a manner as to cover at least part of the wiring
electrode. Hence, the leakage oscillation is damped by the resin layer.

[0017]In still another specific aspect of the piezoelectric oscillator
part according to the present invention, the piezoelectric oscillator
part further includes a cap, having an opening on the substrate side of
the cap, fixed to the substrate using adhesive in such a manner as to
surround the piezoelectric oscillator. Consequently, a piezoelectric
oscillator part may be provided that has a packaging structure including
a sealed space, formed in accordance with the present invention, for
preventing the displacement of a piezoelectric oscillator from being
hindered and that also allows for the suppression of leakage oscillation
in accordance with the present invention.

[0018]Also in this structure, a resin layer formed on the upper surface of
the substrate is preferably provided in such a manner as to cover at
least part of the wiring electrodes, whereby the oscillation which leaks
to the substrate side is damped by the resin layer. In this case, the
adhesive for fixing the cap to the substrate may be made to function also
as the above-described resin layer. In this case, it is not necessary to
prepare a different material for forming the resin layer when the
piezoelectric oscillator part with a cap is to be manufactured. Further,
the resin layer may be formed at the same time as the cap combining
operation.

[0019]In the piezoelectric oscillator part according to the present
invention, since a conductive holding member is provided close to one end
of the substrate and a terminal electrode is provided close to the other
end of the substrate, a sufficiently long wiring electrode may be formed.
This allows oscillation that leaks from the piezoelectric oscillator to
the substrate side to be sufficiently attenuated while propagating
through the long wiring electrode. In other words, the length of a path
for attenuation of oscillation using the wiring electrode can be made
long. Furthermore, since the length of the wiring electrode is increased
by devising an effective positional relationship between the terminal
electrode and the conductive holding member, the oscillation attenuation
path length can be increased without increasing the dimensions of the
substrate. Hence, a reduction in the size of a piezoelectric oscillator
part is not prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is an exploded perspective view of a piezoelectric oscillator
part according to a first embodiment of the present invention.

[0021]FIG. 2 is a perspective view for illustrating the process of
combining a cap with a substrate at the time of manufacturing the
piezoelectric oscillator part according to the first embodiment.

[0022]FIG. 3(a) is a schematic front sectional view of a
finite-element-method-based analysis model of the piezoelectric part
provided with a resin layer according to the first embodiment, and FIG.
3(b) illustrates the analysis result of the displacement distribution
based on a finite element method.

[0023]FIG. 4(a) a schematic front sectional view of a
finite-element-method-based analysis model of a modification of the first
embodiment having a configuration similar to the first embodiment except
that the resin layer is not provided, and FIG. 4(b) illustrates the
analysis result of the displacement distribution based on a finite
element method.

[0024]FIG. 5 illustrates the relation between the length of a wiring
electrode and the relative displacement at the wiring electrode.

[0025]FIG. 6(a) is an exploded perspective view of a piezoelectric
oscillator part according to a second embodiment of the present
invention, and FIG. 6(b) is a perspective view for illustrating a cap
combining process at the time of manufacturing the piezoelectric
oscillator part according to the second embodiment.

[0026]FIG. 7 is an explanatory exploded perspective view of a
piezoelectric oscillator part according to a modification of the first
embodiment.

[0063]Hereinafter, specific embodiments of the present invention are
described to clarify the present invention with reference to the
drawings.

[0064]FIG. 1 is an exploded perspective view of a piezoelectric oscillator
part according to a first embodiment of the present invention, and FIG. 2
is a perspective view for illustrating the process of combining the
piezoelectric oscillator part with a cap thereof.

[0065]A piezoelectric oscillator part 1 includes a case substrate 2 having
the shape of an approximately rectangular plane. The rectangular-shaped
plane has first and second short sides 2a and 2b facing each other, and
first and second long sides 2c and 2d facing each other. The four corner
portions of the case substrate 2 are respectively denoted by first to
fourth corner portions A to D. The corner portions A and B are corner
portions located at the respective ends of the first short side 2a, and
the corner portions C and D are corner portions located at the respective
ends of the second short side 2b. The first long side 2c is located
between the corner portions B and D, and the second long side 2d is
located between the corner portions A and C.

[0066]In each of the corner portions A to D, a portion of the case
substrate 2 is cut off to form a concavity having a cylindrical curved
surface. Each of the concavities, is provided with a conductive material
to form an electrode. In other words, a first terminal electrode 3 is
formed in the corner portion B, and a second terminal electrode 4 is
formed in the corner portion C. Dummy electrodes 5 and 6 are respectively
formed in the corner portions A and D.

[0067]The dummy electrodes 5 and 6 need not be formed. However, the
operation of providing an electrode material for forming the terminal
electrodes 3 and 4 becomes easier when electrodes are formed in all of
the corner portions A to D, as in the present embodiment.

[0068]On the upper surface 2e of the case substrate 2, first and second
wiring electrodes 7 and 8 are formed so as to be connected, each at one
end thereof, to the first and second terminal electrodes 3 and 4,
respectively. First and second conductive holding members 9 and 10 are
arranged at the other end thereof of each of the wiring electrodes 7 and
8.

[0069]Examples of the materials which can be used for forming the first
and second wiring electrodes 7 and 8, the terminal electrodes 3 and 4,
and the dummy electrodes 5 and 6 include appropriate metals such as Ag
and Ag--Pd alloy, although not limited to specific materials.

[0070]Using the first and second conductive holding members 9 and 10, a
piezoelectric oscillator 11 is fixed to the case substrate 2 in such a
manner as to be supported by a cantilever structure.

[0071]The piezoelectric oscillator 11 includes a rectangular piezoelectric
plate 12, a first oscillation electrode 13 formed on the first main
surface of the piezoelectric plate 12, a second oscillation electrode
(not shown) formed on the second main surface of the piezoelectric plate
12 so as to face the first oscillation electrode 13 with the
piezoelectric plate 12 therebetween. The piezoelectric plate 12, which is
made of a piezoelectric ceramic or crystal, oscillates in, for example, a
thickness extensional mode. Hence, by applying an alternating voltage
across the first oscillation electrode 13 and the second oscillation
electrode, the piezoelectric oscillator 11 oscillates in a thickness
extensional mode.

[0072]In the piezoelectric oscillator 11, the first oscillation electrode
13 is electrically connected to a terminal electrode 15 provided in one
of the corner portions of the piezoelectric plate 12. The terminal
electrode 15 is positioned above the first conductive holding member 9.

[0073]On the other hand, a second terminal electrode 16 electrically
connected to the second oscillation electrode formed on the lower surface
of the piezoelectric plate 12 is provided in the vicinity of another
corner portion of the piezoelectric plate 12. The second conductive
holding member 10 is positioned below the second terminal electrode 16.
Hence, by combining the piezoelectric oscillator 11 with the case
substrate 2 with the first and second conductive holding members 9 and
10, the terminal electrodes 15 and 16 are respectively connected to the
first and second terminal electrodes 3 and 4.

[0074]As described above, the first and second conductive holding members
9 and 10 mechanically support the piezoelectric oscillator 11, and also
electrically connect the first oscillation electrode 13 and the second
oscillation electrode of the piezoelectric oscillator 11 respectively to
the first and second terminal electrodes 3 and 4 provided on the case
substrate 2.

[0075]A cap 17 having an opening therebelow is combined with the upper
surface 2e of the case substrate 2 using a rectangular-frame-shaped
adhesive layer 18 so as to cover the piezoelectric oscillator 11. This
seals the piezoelectric oscillator 11 in a package constituted by the
case substrate 2 and the cap 17. The cap 17 is made of, for example, a
composite material in which a metal film is formed on the surface of a
metal or an insulating material.

[0076]In the piezoelectric oscillator part 1, the oscillation that leaks
from the piezoelectric oscillator 11 to the case substrate 2 side is
effectively suppressed because a second wiring electrode 8 is made
sufficiently long. In other words, the second conductive holding member
10 is arranged on the one end side of the case substrate 2, more
specifically, close to the first short side 2a, and the first terminal
electrode 4 is arranged on the other end side, i.e., in the corner
portion C located on the opposite side at the second short side 2b.
Hence, the second wiring electrode 8 extends along the second long side
2d. Therefore, the second wiring electrode 8 is made sufficiently long,
compared with the second wiring electrode 109 of the conventional
piezoelectric oscillator part illustrated in FIG. 8. Consequently, when
the oscillation leaking through the second conductive holding member 10
propagates over the second wiring electrode 8, the leakage oscillation is
sufficiently attenuated. This makes it possible to improve the
oscillation characteristics output from the first and second terminal
electrodes 3 and 4.

[0077]In addition, in the piezoelectric oscillator part 1, a portion of
the second wiring electrode 8 is covered with the adhesive layer 18. In
the present embodiment, the adhesive layer 18 is made of epoxy adhesive,
and since the adhesive layer 18 covers a portion of the second wiring
electrode 8, the leakage oscillation is further attenuated due to the
existence of the adhesive layer.

[0078]Note that a resin layer 20 may be formed at a location schematically
shown by a one-dot chain line illustrated in FIG. 1 to attenuate the
above-described leakage oscillation. In this case, the adhesive layer 18
need not cover the second wiring electrode 8. Materials used for forming
such a resin layer may be the same as those used for forming the adhesive
layer 18. Then the number of kinds of materials to be prepared is
decreased, since the adhesive layer 18 and the resin layer 20 are made of
the same material. In addition, the resin layer 20 may be formed using
the same process as for the adhesive layer 18.

[0079]However, the resin layer 20 may be formed of a resin different from
that of the adhesive layer 18. Examples of such resins include silicone,
urethane resin, and polyimide.

[0080]Hereinafter, it is explained that the leakage oscillation is
suppressed by forming the above-described resin layer, with reference to
an illustration of the analysis result using a finite element method.

[0081]FIGS. 4(a) and (b) illustrate the analysis result of a comparative
example having a configuration similar to that of the above embodiment
except that the resin layer is not provided, i.e., the
rectangular-frame-shaped adhesive layer 18 is formed so as not to cover
the second wiring electrode 8, where 4(a) is a schematic front sectional
view of the analysis model, and 4(b) illustrates the analysis result of
the displacement distribution based on a finite element method. On the
other hand, FIG. 3(a) is a schematic front sectional view of the analysis
model of the piezoelectric oscillator part of the above-described
embodiment, and FIG. 3(b) is an illustration of the analysis result of
the displacement distribution thereof.

[0082]In the analysis model illustrated in FIG. 4(a), a schematic
structure is illustrated in which a wiring electrode 122 on the case
substrate is located below a piezoelectric oscillator 121. In FIG. 3(a),
a schematic structure is illustrated in which the resin layer 20 is
formed on the second wiring electrode 8 on the case substrate located
below the piezoelectric oscillator 11.

[0083]FIG. 4(b) shows that, compared with FIG. 3(b), the second wiring
electrode is not displaced so much since the leakage oscillation is
suppressed by formation of the resin layer 20. In other words, it can be
seen that the leakage oscillation is effectively suppressed by formation
of the resin layer 20.

[0084]Note that in the analysis illustrated in FIGS. 3(b) and 4(b), the
following assumption was made: the piezoelectric oscillator is a crystal
oscillator, the electrode material is Ag, the density of piezoelectric
material is 1.04×104 kg/m3, the Young's modulus is
7.32×103 Pa, and the mechanical attenuation (1/Qm) is
100×10-3; and regarding the resin constituting the resin layer
20, the density is 1.2×103 kg/m3, the Young's modulus is
4×109 Pa, and the mechanical attenuation (1/Qm) is 1.

[0085]Further, the relation between the length d/D of the second wiring
electrode on the case substrate and the relative displacement at the
terminal electrode side end of the second wiring electrode has been
obtained on the basis of the result of the analysis using a finite
element method. This result is illustrated in FIG. 5. Note that the
length d of the second wiring electrode is a value normalized by the
width D of the piezoelectric oscillator, and the relative displacement is
a value normalized by the maximum displacement of the piezoelectric
oscillator 11.

[0086]As can be clearly seen from FIG. 5, the relative displacement at the
terminal electrode side end of the second wiring electrode decreases as
the length of the second wiring electrode increases. This shows that the
relative displacement can be decreased in accordance with an increase in
the length of the second wiring electrode both in the case of the
modification in which the resin layer 20 is not provided, as indicated by
◯, and in the case of the above-described embodiment in which
the resin layer 20 is provided, as indicated by quadrature.

[0087]In addition, it can be seen that according to the above-described
embodiment in which the resin layer 20 is provided, compared with the
modification in which the resin layer 20 is not provided, the relative
displacement can be decreased by forming a resin layer when making a
comparison of the second wiring electrodes of the same length.

[0088]Note that although the length of the second wiring electrode, among
the first and second wiring electrodes, is increased in the present
embodiment to suppress the leakage oscillation, the length of the first
wiring electrode may instead be increased.

[0089]Furthermore, the resin layer 20 need not be formed in such a manner
as to cover the whole lengthened wiring electrode, and may be formed in
such a manner to cover a portion of the first wiring electrode.
Preferably, the resin layer is formed in such a manner as to cover
portions of both the first and second wiring electrodes, thereby
effectively suppressing the leakage oscillation.

[0090]FIG. 6(a) is an exploded perspective view of a piezoelectric
oscillator part according to a second embodiment of the present
invention, and FIG. 6(b) is a perspective view for illustrating the
process of combining the piezoelectric oscillator part with a cap
thereof.

[0091]In a piezoelectric oscillator part 31 according to the second
embodiment, electrodes are formed in corner portions A to D of a case
substrate 32 similarly to the case substrate 2 of the above-described
embodiment. Here, a first terminal electrode 33 is formed in the corner
portion B, and a second terminal electrode 34 is formed in the corner
portion C, and dummy electrodes 35 and 36 are respectively formed in the
corner portions A and D. In the present embodiment, a first wiring
electrode 37 one end of which is connected to the first terminal
electrode 33 and a second wiring electrode 38 one end of which is
connected to the second terminal electrode 34 are formed in such a manner
as to respectively have sufficient lengths. This is because a
piezoelectric oscillator 41 is supported at one end and the other end
thereof.

[0092]More specifically, the case substrate 32 has the shape of a
rectangular plane. The rectangular-shaped plane has first and second
short sides 32a and 32b facing each other, and first and second long
sides 32c and 32d facing each other. The first terminal electrode 33 is
arranged close to the first short side 32a and a first conductive holding
member 39 is arranged close to the second short side 32b. Hence, the
first wiring electrode 37 electrically connecting the first terminal
electrode 33 and the first conductive holding member 39 has a sufficient
length. Similarly, the second terminal electrode 34 is formed in the
corner portion of the second short side 32b, and a second conductive
holding member 40 is arranged close to the first short side 32a. Hence,
the second wiring electrode 38 is formed in such a manner as to have a
sufficient length similarly to the first embodiment.

[0093]The piezoelectric oscillator 41 has first and second terminal
electrodes 45 and 46 respectively above the first and second conductive
holding members 39 and 40. The first terminal electrode 45 extends from
the upper surface of a piezoelectric plate 42 to the lower surface
thereof via the side thereof. This portion which extends to the lower
surface of the piezoelectric plate 42 is connected to the upper surface
of the first conductive holding member 39, and they are electrically
connected.

[0094]Note that also in the piezoelectric oscillator 41, the piezoelectric
plate 42 is divided into two polarities in the thickness direction: a
first oscillation electrode 43 is formed on the upper surface and a
second oscillation electrode (not illustrated) is formed on the lower
surface. The first and second terminal electrodes 45 and 46 are
respectively connected to the first and second oscillation electrodes.
The piezoelectric oscillator part 31 of the second embodiment is similar
to that of the first embodiment except that the structure of supporting
the piezoelectric oscillator 41 is different, as described above, and
hence, the length of the first wiring electrode 37 and the position of
the first conductive holding member 39 are different. Hence, description
of the adhesive layer 18 and the cap 17 is omitted here and the
description in the first embodiment is to be referred to.

[0095]Also in the present embodiment, since the second wiring electrode 38
has a sufficient length, the oscillation that leaks via the second
conductive holding member 40 is attenuated while propagating through the
second wiring electrode 38. In addition, also in the first wiring
electrode 37, the leaking oscillation is sufficiently attenuated.
Consequently, the oscillation is attenuated by both the first and second
wiring electrodes 37 and 38 in the second embodiment, and hence, better
resonance characteristics are obtained.

[0096]Further, also in the present embodiment, the adhesive layer 18 also
plays the role of a resin layer that attenuates oscillation, and hence,
the adhesive layer 18 is formed in such a manner as to cover part of the
first and second wiring electrodes 37 and 38.

[0097]However, similarly to the first embodiment, a resin layer for
attenuating the oscillation may be formed in such a manner as to cover at
least a portion of at least one of the first and second wiring
electrodes, separately from the adhesive layer 18.

[0098]Note that although the wiring electrode 8 is lengthened in the
embodiment illustrated in FIG. 1, a first wiring electrode 7 may also be
lengthened by being made to extend to a second short side 2b side, as in
a piezoelectric oscillator part 51 of a modification of the embodiment
illustrated in FIG. 7. Here, a terminal electrode 3 is arranged in the
corner portion of the second short side 2b and a first long side 2c, and
the wiring electrode 7 is electrically connected to the terminal
electrode 3. Hence, in a corner portion B of a first short side 2a and
the first long side 2c, a dummy electrode 6 is formed.

[0099]The piezoelectric oscillator part 51 is similar to the piezoelectric
oscillator part 1 in other respects. In this manner, all the terminal
electrodes may be formed close to one side of a piezoelectric substrate.

[0100]Although a piezoelectric oscillator is used in which the first and
second oscillation electrodes are formed on part of the first and second
main surfaces of the piezoelectric plate in the first and second
embodiments, other types of piezoelectric oscillators may be used. In
other words, various energy-confined piezoelectric oscillators may be
used in the present invention.